مهرداد عنبریان

Purpose:  Prophylactic effect of PNF stretching is performed with an expectation to reduce the risk of eccentric exercise-induced muscle damage and enhance drop jump performance.The purpose of this study was to examine the effects of proprioceptive neuromuscular facilitation stretching combined with plyometric training on deep jump in non-athlete male students. Method: The study design was a single blinded, randomized, concurrent parallel trial. Forty-two non-athlete male students were volunteered to participate in this study. Participants were assigned into plyometric (n=21) and plyometric & PNF (n=21) groups. Maximum and minimum vertical displacements, flight time, joint power, maximum landing force, peak take off instantaneous velocity were measured at baseline and 48 hours following the plyometric exercise protocol. A Vicon (200 Hz) motion analysis system with six T-Series cameras and two Kistler force plates (1000 HZ) were used to record kinematic and kinetic data, respectively. A two-way repeatedmeasure ANOVA (group x DOMS) was used to analyze data. Results: There was a significant difference between the pretest and the posttest scores in the intervention group for maximum vertical displacement (p=0.028), flight time (p=0.042), and Power average (p=0.026). Conclusions: This prophylactic treatment on mechanical parameters of deep jump during timing was useful. Eventually, results suggest that preventative treatments can have a significant effect on maintenance functional parameters or even helping to slow exercise-induced muscle damage for alleviating its symptoms.

Background : Cold sprays (CS) are widely used in sport competitions as an effective, simple, and high available treatment. Aim: The aim of present study was to investigate immediate and longtime effects of CS application onto the knee joint anterior-medial area of dominant leg on timing and activation pattern of selected muscles during one-leg landing. Materials and Methods: Thirty (15 control and 15 experimental) able-bodied male participated in this study. Electromyography activity of vastus medialis, rectus femoris, vastus lateralis, biceps femoris, semiendineus and medial gastrocnemius were recorded during one-leg landing tests (with dominant leg) for each of three conditions including before CS application (pre-test), immediately after (post-test 1), and 20 min later (post-test 2). To determine the effect of group and time on each dependent variable, three independent 2×2 multivariate repeated measures analyses of variance were performed (α < 0.05). Results : The results showed following trends rather than significant differences: the muscles in the experimental group had lower activity level and later onset immediately after CS application compared to before application, and they had higher activity level and sooner onset after 20 min from removing CScompared to immediate application. No significant interaction was found for normalized peak activation and time to peak activation ( P > 0.05). However, decrease in skin temperature after cold spray application was observed. Conclusion : These results show short-time cold application, which is so practical after many injuries for returning athletes to sport environment, may not predispose individuals to risk of re-injury or failed landing mechanism.